Carburetor



June 27, 1967 Um ET AL CARBURETOR Filed Dec. 23, 19.65

4 mm L.

Jaw/[J FMA/mWs/r/ INVENTORS' ,4 7- TOR/V5 Y5 United States Patent 3,328,010 CARBURETOR Michael L. Urich, Rochester, and Jerome J. Frankowski,

Warren, Mich, assignors to Holley Carburetor Company, Warren, Mich., a corporation of Michigan Filed Dec. 23, 1965, Ser. No. 516,053 1 Claim. (Cl. 261-34) This invention relates generally to accelerating pumps and more particularly to linkage mechanisms therefor.

When an engine is called upon to accelerate rapidly, the air flow through the carburetor responds almost immediately to the increased throttle opening; however, the fuel which is heavier than air, lags a substantial amount behind the increased air flow, thereby causing a leaning out of the fuel-air ratio. The accelerating pump is designed to correct this condition by supplying liquid fuel until the other fuel metering systems once again are providing the proper mixture.

Since accelerating pumps generally come into operation for only very short periods of time and since they are often called upon to provide additional fuel at times when the vehicle could be in danger if it did not move rapidly, such as in passing or entering a line of traflic, it is apparent that it is extremely important for the linkage mechanism between the throttle lever and the accelerating pump to be of a type which causes the accelerating pump to respond immediately and Without any hesitations whatsoever when the throttle is suddenly opened.

Prior art linkage mechanisms have included link and rod combinations which tended to cock and bind with one another, thereby preventing the required smooth operation. Since the usual link and rod tends to buckle in some manner as the link is rotated by the throttle lever, friction between these parts progressively increases when they are directly connected together.

Accordingly, a general object of the invention is to provide a novel accelerating pump linkage mechanism which performs the above mentioned smooth working operation.

Another object of the invention is to provide such a mechanism which includes means connected between the usual link and rod for eliminating sliding metal friction.

A further object of the invention is to provide such a mechanism wherein a member constructed from a low friction material serves as a movable pivot point between the link and the rod, as a guide for the link, and as a retainer for the usual pump drive spring.

Other objects and advantages of the invention will become more apparent when reference is made to the following specification -and the accompanying drawings wherein:

FIGURE 1 is a fragmentary side elevational view of a prior art carburetor;

FIGURE 2 is a fragmentary side elevational view of a carburetor embodying the invention;

FIGURE 3 is a fragmentary top plan view taken along the plane of line 33 of FIGURE 2 and looking in the direction of the arrows; and

FIGURE 4 is a cross-sectional view taken along the plane of line 44 of FIGURE 2 and looking in the direction of the arrows.

Referring to the drawings in greater detail, FIGURES 1-3 illustrate a carburetor having a body 12 with an induction passage 14 extending therethrough. The carburetor is provided with the usual throttle valve 18, mounted on the shaft 20 for controlling the flow of combustible mixture to the engine intake manifold 22 and the usual throttle lever 24 operatively connected to the shaft 20.

The accelerating pump assembly 26 supplies fuel from the usual fuel reservoir 28 to the induction passage 14 in the usual manner. Since the accelerating pump assembly 26 forms no part of the invention, certain internal details associated therewith need not be illustrated. For purposes of the invention, it is sufiicient to know that the accelerating pump 26 will be initiated in response to rapid actuation of the accelerator pedal (not shown), which, in turn, rotates the usual throttle lever 24 about the shaft 20 through a connection (not shown) between the accelerator pedal and an opening 30 formed in the throttle lever.

In prior art carburetors, a typical linkage mechanism 32 between the throttle lever 24 and the accelerating pump assembly 26 is as illustrated in FIGURE 1. Such a linkage mechanism 32 generally comprises a link member 34 and a rod member 36, the link member including an abutment 38 formed on one end thereof and being connected to the throttle lever 24 by the other end 40 thereof, and the rod member 36 having one end connected to the usual accelerating pump stem 42 and the other end connected around the link member 34. The latter end of the rod member includes a fiat portion 44 having an opening 46 formed therethrough for insertion of the linkage member 34, the opening 46 being larger in diameter than the diameter of the link member 34 for a purpose to be described. As the throttle lever 24 is rotated, the adjoining end of the link member 34 is rotated upwardly in FIG- URE l, causing the usual pump drive spring 48, which surrounds the link member 34, to become compressed by the relative movement of the fiat end 44 of the rod member 36 along the link member 34.

It may be noted in FIGURE 1, that the link member 34 is bowed slightly in order that movement of the link member through the opening 46 may be facilitated. Obviously, the resultant leftward (FIGURE 1) movement of the end 44 of the rod member 36 would cause the other end thereof which is connected to the pump stem 42 to rotate downwardly, the intermediate portion of the rod serving as a fulcrum point and lateral movement being prevented by any suitable means, such as a cover 47. Experience shows that movement of the end 44 of the rod member 36 along the link member 34 is considerably hampered by the progressively changing frictional relationship between the two members, resulting in an inefficient actuation of the accelerating pump 26.

As illustrated in FIGURES 2 and 3, the invention contemplates the use of a novel linkage mechanism 48 including a link member 50, a rod member 52, a pump spring 54 and a co-operating guide 56. It may be noted that the link member 50 consists of flat rather than round stock and includes a shoulder 57 formed near the throttle lever end thereof. A pair of openings 58 and 59 are formed in the throttle lever end for optional connection with the lever 24. An elongated opening 60 is formed adjacent the other end thereof, through which an end of the link member 52 extends. The width of the elongated opening 60 is slightly greater than the diameter of the inserted end of the rod member 52.

Prior to insertion of the end of the rod 52 in the elongated opening 60, the pump link guide 56, which may be better seen in cross-section in FIGURE 4, is inserted over the end of the link member 50, thereby compressing the spring 54 a predetermined amount. The guide 56 includes a rectangular full length opening 62 for this purpose. A transverse circular opening 64 is formed through the guide at right angles to the plane of the opening 62, the end of the rod member 52 being inserted through this circular opening. A slot 66 (FIGURE 2) is formed through the guide 56 adjacent the circular opening 64, for insertion of a tab 68 formed adjacent the end of the rod member 52. A similar tab 70 (FIGURE 3) is formed on the rod 52 on the opposite side of the guide member 56 to prevent lateral movement between the rod 52 and the guide 56. In assembly, the tab 68 is inserted through the slot and the rod member 52 then rotated slightly.

As better seen in FIGURE 4, the relationship between the rectangular opening 62 and the circular opening 64, and the resultant relationship between the opening 60 in the link member 50 and the diameter of the rod member 52 are such that the rod member 52 may move up and down within the elongated opening 60, while a clearance 66 is maintained at all times between the outer diameter of the rod member 52 and the wall forming the opening 60.

Operation As is well known in the art, actuation of the throttle lever 24, resulting from rapid depression of the usual accelerator pedal, will cause the axis of the connection between the throttle lever 24 and the link member 50 to pivot upwardly in FIGURE 2 in a clockwise direction. This, in turn, will move the upper end of the link member 50 upwardly so that the end of the rod member 52, which is retained by the cover 47 will move along the slot 60 due to the pivotal connection between the rod member 52 and the link 50. This compresses the spring 54, which, in turn, rotates the rod 52 and forces the accelerating pump stem 42 downwardly, thus performing the operation of supplying additional fuel during the acceleration period.

As previously indicated, the operation just described will be highly efficient due to the use of the guide member 56 in the linkage mechanism 32. In other words, the clearance 66, previously described, will be maintained throughout all phases of the linkage mechanism operation, thus eliminating any chance for a frictional impediment to the relative movements between the link member 50 and the rod 52. That is, the relative movement between the link 50 and the guide 56, which may be made from a material such as Delrin or a suitable oil impregnated sintered metal, will be virtually frictionless.

Besides serving as a low friction guide and swivel for the relative movements just described, it is apparent that the guide member 56 also serves as a retainer for the spring 54. Once the accelerating pump assembly 26 bottoms during the pressure stroke, further movement of the accelerator pedal will continue to rotate the throttle lever 24 and move the link member 50, even though the rod member 52 will have been stopped, this continued movement being possible due to the slot 60 allowing the link member 50 to continue to move past the now stopped rod member 52.

If it is desired, the pump stroke may be changed by connecting the link member 50 to the throttle lever 24 through the opening 59, rather than the opening 58.

It should be apparent that the linkage mechanism 48 illustrated in FIGURES 2 and 3 is considerably more efficient than the linkage mechanism 32 illustrated in FIGURE 1, the improvement being a smoothly function ing pivotal connection between the link member and the rod member 52, and, hence, a smooth, rather than jerky operation of the accelerating pump assembly 26.

While but one embodiment of the invention has been shown and described, it is apparent that other modifications of the invention are possible within the scope of the appended claim.

What we claim as our invention is:

A carburetor, comprising a body formed to provide an induction passage with a throttle valve therein mounted on a pivotable shaft having a throttle operating lever connected to one end thereof, an accelerating pump having a pivotable operating lever connected thereto, a link having one end connected to said throttle lever and the other end thereof connected to said pump operating lever, an element preventing dire-ct contact between said link and said pump lever, said element being formed from a low friction material and having a first passage extending therethrough receiving said link and a second passage extending therethrough at right angles to and intersecting said first passage and receiving said pump lever, said link having a shoulder near the end thereof connected to said throttle lever, a compression coil spring surrounding said link, the ends of said spring being seated on said shoulder and said element, said link having a slot formed therein receiving said pump lever and providing a lost motion connection therewith, whereby when said throttle is opened said link is moved toward said pump lever to compress said spring without operating said pump lever except by the force of said compressed spring, said element extending toward the throttle lever end of said link a sufficient distance to provide a guide for said link to at all times maintain said link and said pump lever at right angles to one another.

References Cited UNITED STATES PATENTS 2,076,606 4/1937 Winter 261-34 X 2,080,569 5/1937 Holley 26134 X 2,633,085 3/1953 Hiege-r 26134 X 2,639,778 4/1953 Puro 261-34 X 3,189,330 6/1965 Newman 26134 3,269,711 8/1966 Baldwin 261--34 FOREIGN PATENTS 1,295,587 4/1962 France.

OTHER REFERENCES Quadrajet, Rochester Products, Rochester, N.Y., Bulletin 9D-5 October 1965, pp. 1, 13 and 16 relied on.

HARRY B. THORNTON, Primary Examiner.

T. R. MILES, Assistant Examiner, 

